The movement to speak out against gun violence — and call for stricter gun control measures — was sparked largely by the outspokenness of a handful of students from Marjory Stoneman Douglas High School, where 17 people were killed in the deadly Feb. 14 shooting. Many of them believe Congress and White House leadership have not done enough, so they're taking to the streets.

Here is a list of where people are marching Saturday, and when. All times are local: